Coverage Report

Created: 2024-11-21 07:03

/src/mbedtls/library/psa_crypto_ffdh.c
Line
Count
Source (jump to first uncovered line)
1
/*
2
 *  PSA FFDH layer on top of Mbed TLS crypto
3
 */
4
/*
5
 *  Copyright The Mbed TLS Contributors
6
 *  SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later
7
 */
8
9
#include "common.h"
10
11
#if defined(MBEDTLS_PSA_CRYPTO_C)
12
13
/* This header is only needed because it defines
14
 * MBEDTLS_DHM_RFC7919_FFDHEXXXX_[P|G]_BIN symbols that are used in
15
 * mbedtls_psa_ffdh_set_prime_generator(). Apart from that, this module
16
 * only uses bignum functions for arithmetic. */
17
#include <mbedtls/dhm.h>
18
19
#include <psa/crypto.h>
20
#include "psa_crypto_core.h"
21
#include "psa_crypto_ffdh.h"
22
#include "psa_crypto_random_impl.h"
23
#include "mbedtls/platform.h"
24
#include "mbedtls/error.h"
25
26
#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_EXPORT) ||   \
27
    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_GENERATE) ||   \
28
    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_PUBLIC_KEY) || \
29
    defined(MBEDTLS_PSA_BUILTIN_ALG_FFDH)
30
static psa_status_t mbedtls_psa_ffdh_set_prime_generator(size_t key_size,
31
                                                         mbedtls_mpi *P,
32
                                                         mbedtls_mpi *G)
33
0
{
34
0
    const unsigned char *dhm_P = NULL;
35
0
    const unsigned char *dhm_G = NULL;
36
0
    size_t dhm_size_P = 0;
37
0
    size_t dhm_size_G = 0;
38
0
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
39
40
0
    if (P == NULL && G == NULL) {
41
0
        return PSA_ERROR_INVALID_ARGUMENT;
42
0
    }
43
44
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_2048)
45
0
    static const unsigned char dhm_P_2048[] =
46
0
        MBEDTLS_DHM_RFC7919_FFDHE2048_P_BIN;
47
0
    static const unsigned char dhm_G_2048[] =
48
0
        MBEDTLS_DHM_RFC7919_FFDHE2048_G_BIN;
49
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_2048 */
50
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_3072)
51
0
    static const unsigned char dhm_P_3072[] =
52
0
        MBEDTLS_DHM_RFC7919_FFDHE3072_P_BIN;
53
0
    static const unsigned char dhm_G_3072[] =
54
0
        MBEDTLS_DHM_RFC7919_FFDHE3072_G_BIN;
55
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_3072 */
56
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_4096)
57
0
    static const unsigned char dhm_P_4096[] =
58
0
        MBEDTLS_DHM_RFC7919_FFDHE4096_P_BIN;
59
0
    static const unsigned char dhm_G_4096[] =
60
0
        MBEDTLS_DHM_RFC7919_FFDHE4096_G_BIN;
61
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_4096 */
62
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_6144)
63
0
    static const unsigned char dhm_P_6144[] =
64
0
        MBEDTLS_DHM_RFC7919_FFDHE6144_P_BIN;
65
0
    static const unsigned char dhm_G_6144[] =
66
0
        MBEDTLS_DHM_RFC7919_FFDHE6144_G_BIN;
67
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_6144 */
68
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_8192)
69
0
    static const unsigned char dhm_P_8192[] =
70
0
        MBEDTLS_DHM_RFC7919_FFDHE8192_P_BIN;
71
0
    static const unsigned char dhm_G_8192[] =
72
0
        MBEDTLS_DHM_RFC7919_FFDHE8192_G_BIN;
73
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_8192 */
74
75
0
    switch (key_size) {
76
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_2048)
77
0
        case sizeof(dhm_P_2048):
78
0
            dhm_P = dhm_P_2048;
79
0
            dhm_G = dhm_G_2048;
80
0
            dhm_size_P = sizeof(dhm_P_2048);
81
0
            dhm_size_G = sizeof(dhm_G_2048);
82
0
            break;
83
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_2048 */
84
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_3072)
85
0
        case sizeof(dhm_P_3072):
86
0
            dhm_P = dhm_P_3072;
87
0
            dhm_G = dhm_G_3072;
88
0
            dhm_size_P = sizeof(dhm_P_3072);
89
0
            dhm_size_G = sizeof(dhm_G_3072);
90
0
            break;
91
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_3072 */
92
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_4096)
93
0
        case sizeof(dhm_P_4096):
94
0
            dhm_P = dhm_P_4096;
95
0
            dhm_G = dhm_G_4096;
96
0
            dhm_size_P = sizeof(dhm_P_4096);
97
0
            dhm_size_G = sizeof(dhm_G_4096);
98
0
            break;
99
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_4096 */
100
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_6144)
101
0
        case sizeof(dhm_P_6144):
102
0
            dhm_P = dhm_P_6144;
103
0
            dhm_G = dhm_G_6144;
104
0
            dhm_size_P = sizeof(dhm_P_6144);
105
0
            dhm_size_G = sizeof(dhm_G_6144);
106
0
            break;
107
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_6144 */
108
0
#if defined(MBEDTLS_PSA_BUILTIN_DH_RFC7919_8192)
109
0
        case sizeof(dhm_P_8192):
110
0
            dhm_P = dhm_P_8192;
111
0
            dhm_G = dhm_G_8192;
112
0
            dhm_size_P = sizeof(dhm_P_8192);
113
0
            dhm_size_G = sizeof(dhm_G_8192);
114
0
            break;
115
0
#endif /* MBEDTLS_PSA_BUILTIN_DH_RFC7919_8192 */
116
0
        default:
117
0
            return PSA_ERROR_INVALID_ARGUMENT;
118
0
    }
119
120
0
    if (P != NULL) {
121
0
        MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(P, dhm_P,
122
0
                                                dhm_size_P));
123
0
    }
124
0
    if (G != NULL) {
125
0
        MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(G, dhm_G,
126
0
                                                dhm_size_G));
127
0
    }
128
129
0
cleanup:
130
0
    if (ret != 0) {
131
0
        return mbedtls_to_psa_error(ret);
132
0
    }
133
134
0
    return PSA_SUCCESS;
135
0
}
136
#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_EXPORT ||
137
          MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_GENERATE ||
138
          MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_PUBLIC_KEY ||
139
          MBEDTLS_PSA_BUILTIN_ALG_FFDH */
140
141
#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_EXPORT) || \
142
    defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_PUBLIC_KEY)
143
psa_status_t mbedtls_psa_ffdh_export_public_key(
144
    const psa_key_attributes_t *attributes,
145
    const uint8_t *key_buffer,
146
    size_t key_buffer_size,
147
    uint8_t *data,
148
    size_t data_size,
149
    size_t *data_length)
150
0
{
151
0
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
152
0
    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
153
0
    mbedtls_mpi GX, G, X, P;
154
0
    psa_key_type_t type = attributes->type;
155
156
0
    if (PSA_KEY_TYPE_IS_PUBLIC_KEY(type)) {
157
0
        if (key_buffer_size > data_size) {
158
0
            return PSA_ERROR_BUFFER_TOO_SMALL;
159
0
        }
160
0
        memcpy(data, key_buffer, key_buffer_size);
161
0
        memset(data + key_buffer_size, 0,
162
0
               data_size - key_buffer_size);
163
0
        *data_length = key_buffer_size;
164
0
        return PSA_SUCCESS;
165
0
    }
166
167
0
    mbedtls_mpi_init(&GX); mbedtls_mpi_init(&G);
168
0
    mbedtls_mpi_init(&X); mbedtls_mpi_init(&P);
169
170
0
    size_t key_len = PSA_BITS_TO_BYTES(attributes->bits);
171
172
0
    status = mbedtls_psa_ffdh_set_prime_generator(key_len, &P, &G);
173
174
0
    if (status != PSA_SUCCESS) {
175
0
        goto cleanup;
176
0
    }
177
178
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&X, key_buffer,
179
0
                                            key_buffer_size));
180
181
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&GX, &G, &X, &P, NULL));
182
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&GX, data, key_len));
183
184
0
    *data_length = key_len;
185
186
0
    ret = 0;
187
0
cleanup:
188
0
    mbedtls_mpi_free(&P); mbedtls_mpi_free(&G);
189
0
    mbedtls_mpi_free(&X); mbedtls_mpi_free(&GX);
190
191
0
    if (status == PSA_SUCCESS && ret != 0) {
192
0
        status = mbedtls_to_psa_error(ret);
193
0
    }
194
195
0
    return status;
196
0
}
197
#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_EXPORT ||
198
          MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_PUBLIC_KEY */
199
200
#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_GENERATE)
201
psa_status_t mbedtls_psa_ffdh_generate_key(
202
    const psa_key_attributes_t *attributes,
203
    uint8_t *key_buffer, size_t key_buffer_size, size_t *key_buffer_length)
204
0
{
205
0
    mbedtls_mpi X, P;
206
0
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
207
0
    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
208
0
    mbedtls_mpi_init(&P); mbedtls_mpi_init(&X);
209
0
    (void) attributes;
210
211
0
    status = mbedtls_psa_ffdh_set_prime_generator(key_buffer_size, &P, NULL);
212
213
0
    if (status != PSA_SUCCESS) {
214
0
        goto cleanup;
215
0
    }
216
217
    /* RFC7919: Traditional finite field Diffie-Hellman has each peer choose their
218
        secret exponent from the range [2, P-2].
219
        Select random value in range [3, P-1] and decrease it by 1. */
220
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_random(&X, 3, &P, mbedtls_psa_get_random,
221
0
                                       MBEDTLS_PSA_RANDOM_STATE));
222
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_sub_int(&X, &X, 1));
223
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&X, key_buffer, key_buffer_size));
224
0
    *key_buffer_length = key_buffer_size;
225
226
0
cleanup:
227
0
    mbedtls_mpi_free(&P); mbedtls_mpi_free(&X);
228
0
    if (status == PSA_SUCCESS && ret != 0) {
229
0
        return mbedtls_to_psa_error(ret);
230
0
    }
231
232
0
    return status;
233
0
}
234
#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_GENERATE */
235
236
#if defined(MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_IMPORT)
237
psa_status_t mbedtls_psa_ffdh_import_key(
238
    const psa_key_attributes_t *attributes,
239
    const uint8_t *data, size_t data_length,
240
    uint8_t *key_buffer, size_t key_buffer_size,
241
    size_t *key_buffer_length, size_t *bits)
242
0
{
243
0
    (void) attributes;
244
245
0
    if (key_buffer_size < data_length) {
246
0
        return PSA_ERROR_BUFFER_TOO_SMALL;
247
0
    }
248
0
    memcpy(key_buffer, data, data_length);
249
0
    *key_buffer_length = data_length;
250
0
    *bits = PSA_BYTES_TO_BITS(data_length);
251
252
0
    return PSA_SUCCESS;
253
0
}
254
#endif /* MBEDTLS_PSA_BUILTIN_KEY_TYPE_DH_KEY_PAIR_IMPORT */
255
256
#if defined(MBEDTLS_PSA_BUILTIN_ALG_FFDH)
257
psa_status_t mbedtls_psa_ffdh_key_agreement(
258
    const psa_key_attributes_t *attributes,
259
    const uint8_t *peer_key,
260
    size_t peer_key_length,
261
    const uint8_t *key_buffer,
262
    size_t key_buffer_size,
263
    uint8_t *shared_secret,
264
    size_t shared_secret_size,
265
    size_t *shared_secret_length)
266
0
{
267
0
    int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
268
0
    psa_status_t status = PSA_ERROR_CORRUPTION_DETECTED;
269
0
    mbedtls_mpi P, G, X, GY, K;
270
0
    const size_t calculated_shared_secret_size = peer_key_length;
271
272
0
    if (peer_key_length != key_buffer_size ||
273
0
        calculated_shared_secret_size > shared_secret_size) {
274
0
        return PSA_ERROR_INVALID_ARGUMENT;
275
0
    }
276
277
0
    if (!PSA_KEY_TYPE_IS_DH_KEY_PAIR(psa_get_key_type(attributes))) {
278
0
        return PSA_ERROR_INVALID_ARGUMENT;
279
0
    }
280
281
0
    mbedtls_mpi_init(&P); mbedtls_mpi_init(&G);
282
0
    mbedtls_mpi_init(&X); mbedtls_mpi_init(&GY);
283
0
    mbedtls_mpi_init(&K);
284
285
0
    status = mbedtls_psa_ffdh_set_prime_generator(
286
0
        PSA_BITS_TO_BYTES(attributes->bits), &P, &G);
287
288
0
    if (status != PSA_SUCCESS) {
289
0
        goto cleanup;
290
0
    }
291
292
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&X, key_buffer,
293
0
                                            key_buffer_size));
294
295
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_read_binary(&GY, peer_key,
296
0
                                            peer_key_length));
297
298
    /* Calculate shared secret public key: K = G^(XY) mod P = GY^X mod P */
299
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_exp_mod(&K, &GY, &X, &P, NULL));
300
301
0
    MBEDTLS_MPI_CHK(mbedtls_mpi_write_binary(&K, shared_secret,
302
0
                                             calculated_shared_secret_size));
303
304
0
    *shared_secret_length = calculated_shared_secret_size;
305
306
0
    ret = 0;
307
308
0
cleanup:
309
0
    mbedtls_mpi_free(&P); mbedtls_mpi_free(&G);
310
0
    mbedtls_mpi_free(&X); mbedtls_mpi_free(&GY);
311
0
    mbedtls_mpi_free(&K);
312
313
0
    if (status == PSA_SUCCESS && ret != 0) {
314
0
        status = mbedtls_to_psa_error(ret);
315
0
    }
316
317
0
    return status;
318
0
}
319
#endif /* MBEDTLS_PSA_BUILTIN_ALG_FFDH */
320
321
#endif /* MBEDTLS_PSA_CRYPTO_C */